Online voting (the kind you could do in the comfort of your own home) suffers from manipulation in the more traditional form: I sit at your house with a baseball bat and make sure you vote for my candidate of choice. Voting at a voting booth prevents that.
I'm generally in favor of overhauling the voting system with technology (especially open source technology that can be publicly validated), but I think there are still benefits to having people vote in a supervised public space making sure people can vote anonymously and safely
You're right. I was actually just about to edit my post to comment on the fact that absentee ballots still suffer that problem, so perhaps my thoughts here are invalid.
However, vote by mail is more likely to suffer from the peanut butter & jelly problem, which is getting food smudged on the ballots while filling them out at the dinner table.
Or I come over to your house and tell you I'll give you $10 to vote for my candidate. If you had to go to a voting booth it might not be worth the effort.
I'm generally in favor of overhauling the voting system with technology (especially open source technology that can be publicly validated), but I think there are still benefits to having people vote in a supervised public space making sure people can vote anonymously and safely